Avalanche Forecast

Issued: Mar 21st, 2017 4:12PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Deep Persistent Slabs.

shorton, Avalanche Canada

Lizard-Flathead.

Freezing levels and precipitation amounts are uncertain for Tuesday night. Watch for touchy wind slabs at higher elevations and stay aware of overhead hazards.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

TUESDAY NIGHT: A short pulse of warm wet weather overnight will bring 10-15 mm of precipitation, strong southwest wind, and freezing level up to 2000 m.WENDESDAY: Cloudy with isolated flurries, strong southwest wins, freezing level dropping to around 1700 m.THURSDAY: Mix of sun and cloud, moderate southwest wind, freezing level around 1600 m with alpine temperatures around -5 C.FRIDAY: Increasing cloud, light wind, alpine temperatures around -1 C.

Avalanche Summary

A few small solar triggered avalanches were reported over the past few days, but there has not been any notable recent activity. A large avalanche cycle occurred during last weekend's storm, including some that stepped down to deeper weak layers well over a metre deep.New snow should form wind slabs at higher elevations, well warming and cornice falls are potential triggers for deep persistent slabs.

Snowpack Summary

Moderate amounts of alpine snow will form wind slabs at higher elevations on Tuesday night. Meanwhile at lower elevations, rain will once again soak the snowpack. A thick rain crust has formed near the surface at all elevations, but tends to break down with daytime warming at lower elevations and on solar aspects. Isolated basal facets exist in shallow snowpack areas and still have the potential to produce destructive full-depth avalanches.

Problems

Wind Slabs

The incoming storm will likely form fresh wind slabs in the lee of exposed terrain.

Use ridges or ribs to avoid pockets of wind loaded snow.If triggered, wind slabs may step down to deeper layers resulting in large avalanches.Be alert to conditions that change with elevation.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Warming and cornice falls are potential triggers for large avalanches on deep weak layers. Be aware of this as a potential overhead hazard when traveling at lower elevations.

Avoid exposure to overhead hazards during periods of rain.Wind slabs or cornices may trigger deep layers and result in large avalanches.Recognize and avoid avalanche runout zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Mar 22nd, 2017 2:00PM